The Collaborative International Dictionary of English v.0.48:

Xylophone \Xy"lo*phone\, n. [Xylo- + Gr. fwnh` sound.]
   [1913 Webster]
   1. (Mus.) Originally, an instrument common among the
      Russians, Poles, and Tartars, consisting of a series of
      strips of wood or glass graduated in length to the musical
      scale, resting on belts of straw, and struck with two
      small hammers; now any similar musical instrument composed
      of a series of bars of graduated length. Called in Germany
      strohfiedel, or straw fiddle.
      [1913 Webster +PJC]

   2. An instrument to determine the vibrative properties of
      different kinds of wood. --Knight.
      [1913 Webster]